Shaped articles of titanium diboride are conventionally used in the manufacture of refractory containers for use in the electrolytic reduction of aluminum. To control the electrical resisticity of the refractory a composite of TiB.sub.2 and BN is formed by blending each in a controlled ratio. The blend is then hot pressed into a billet from which the shaped article is formed. For example, a boat blank, useful as a container to vaporize aluminum, is formed by diamond machining and grinding a cavity from a TiB.sub.2 :BN billet. The entire operation is very labor intensive and also very costly particularly the equipment for perform the fabrication and machining operation, its maintenance and the loss of billet stock due to sawing and grinding.